Maritime New Zealand is laying charges against Sanford Ltd for dumping of oil in New Zealand waters.
It will bring three charges against the fishing company after an investigation involving the Pacinui, a Korean foreign charter fishing vessel.
The charges include illegal discharge of a harmful substance, failing to report the discharge and failure to notify a pollution incident.
The first charge carries a fine of $200,000. The other charges each carry a maximum fine of $100,000.
Maritime New Zealand said the case is due to be called in Timaru District Court on 26 August.
No other details were issued.